Useful Sports Betting Calculations
by Website Staff

Instead of guessing when you place a bet why not use maths to determine if you have an edge. Every sports bettor should be familiar with these four sports handicapping calculations.

Odds Conversion
Most sportsbooks display betting lines in multiple formats including US odds. Some Asian sportsbooks will not offer this option, so it is necessary to convert moneyline odds to decimal or vice versa.

Moneyline favorite (-200) to decimal odds:
= (-100/us odds)+1
= (-100/-200)+1
= 1.5

Decimal favorite (1.5) to moneyline odds:
= 1/(decimal odds -1)*-100
= 1/(1.5 -1)*-100
= -200

Moneyline underdog (+180) to decimal odds:
= (us odds/100)+1
= (180/100)+1
= 2.8

Decimal underdog (2.8) to moneyline odds:
= (decimal odds -1)*100
= (2.8 -1)*100
= +180

Implied Probability
To determine the win percent necessary to breakeven at the offered odds use the implied probability calculation.

Favorite moneyline:
= ML/(ML-100)
= -200/(-200-100)
= .667 = 66.7%

Underdog moneyline:
= 100/(100+ML)
= 100/(100+180)
= .357 = 35.7%

Notice the sum of the teams implied probabilities is 102.4%. The true odds should add up to 100% but the sportsbook has tacked on a 2.4% over round.

Explicit Probability
The true odds of a team winning a game can be estimated by first calculating the implied probabilities of the team and their opponent. Than using the explicit probability calculation to remove the sportsbook juice or vigorish.

For the following examples assume the moneyline odds on Team A are -200 which gives them an implied probability of 66.7% and the moneyline odds on Team B are +180 with an implied probability of 35.7%.

Chance of Team A winning:
= Team A /(Team A + Team B)
= 66.7%/(66.7%+35.7%)
= 65.1%

Chance of Team B winning:
= Team B /(Team A + Team B)
= 35.7%/(66.7%+35.7%)
= 34.9%

With the juice removed the sum of the team's explicit probabilities equals 100% and shows the true odds for each team.

Edge
Knowing the true odds, a team has to win a game can help determine how large of an edge you have over the sportsbook. If the sportsbook is offering moneyline odds of -200 which is an explicit probability of 65.1% but handicapping reveals the same team has a 70% chance of winning.

Calculate the decimal odds for each probability:
= 1 /65.1% or 1 /0.651 = 1.54
= 1 /70% or 1 /0.7 = 1.43

Calculate the handicappers edge:
= (1.54/1.43) -1 = 0.077 or 7.7%

This information can help sports bettors decide how much to bet. If the odds offered by the sportsbook have a greater edge than normal wagers it might be appropriate to increase the size of the bet.